Do you have the stat for fewest games lost in a slam? I would assume all of Borg, Fed and Nadal would be in there, maybe McEnroe and Lendl as well? (For Nadal, I'm pretty sure RG 2008 would make the list).

1. Borg lost 32 games in 1978 French Open.
2. Borg lost 38 games in 1980 French Open.
3. Nadal lost 41 games in 2008 French Open.

Federer's best was losing 68 games at 2006 Wimbledon. This was the second fewest loss ever at Wimbledon.